Re: [Gluster-users] Replica 2 Quorum and arbiter

[Mahdi Adnan]

Thank you very much.

--

Respectfully
Mahdi A. Mahdi


From: Karthik Subrahmanya <ksubr...@redhat.com>
Sent: Wednesday, April 19, 2017 4:30:30 PM
To: Mahdi Adnan
Cc: gluster-users@gluster.org
Subject: Re: [Gluster-users] Replica 2 Quorum and arbiter

Hi,
Comments inline.

On Tue, Apr 18, 2017 at 1:11 AM, Mahdi Adnan 
<mahdi.ad...@outlook.com<mailto:mahdi.ad...@outlook.com>> wrote:

Hi,


We have a replica 2 volume and we have issue with setting proper quorum.

The volumes used as datastore for vmware/ovirt, the current settings for the 
quorum are:

cluster.quorum-type: auto
cluster.server-quorum-type: server
cluster.server-quorum-ratio: 51%


Losing the first node which hosting the first bricks will take the storage 
domain in ovirt offline but in the FUSE mount point works fine "read/write"

This is not possible. When the client quorum is set to auto and the replica 
count is 2, the first node should be up for read/write to happen from mount. 
May be you are missing something here.

Losing the second node or any other node that hosts only the second bricks of 
the replication will not affect ovirt storage domain i.e 2nd or 4th ndoes.

Since the server-quorum-ratio is set to 51%, this is also not possible.
Can you share the volume info here?

As i understand, losing the first brick in replica 2 volumes will render the 
volume to read only

Yes you are correct, loosing the first brick will make the volume read-only.

, but how FUSE mount works in read write ?

Also, can we add an arbiter node to the current replica 2 volume without losing 
data ? if yes, does the re-balance bug "Bug 1440635" affect this process ?
Yes you can add an arbiter brick without losing data and the bug 1440635 will 
not affect that, since only the metadata need to be replicated on the arbiter 
brick.
And what happen if we set "cluster.quorum-type: none" and the first node goes 
offline ?
If you set the quorum-type to auto in a replica 2 volume, you will be able to 
read/write even when only one brick is up.
For an arbiter volume, quorum-type is auto by default and it is the recommended 
setting.

HTH,
Karthik

Thank you.

--

Respectfully
Mahdi A. Mahdi


___
Gluster-users mailing list
Gluster-users@gluster.org<mailto:Gluster-users@gluster.org>
http://lists.gluster.org/mailman/listinfo/gluster-users

___
Gluster-users mailing list
Gluster-users@gluster.org
http://lists.gluster.org/mailman/listinfo/gluster-users

Re: [Gluster-users] Replica 2 Quorum and arbiter

[Mahdi Adnan]

Thank you very much.

--

Respectfully
Mahdi A. Mahdi


From: Karthik Subrahmanya <ksubr...@redhat.com>
Sent: Wednesday, April 19, 2017 4:30:30 PM
To: Mahdi Adnan
Cc: gluster-users@gluster.org
Subject: Re: [Gluster-users] Replica 2 Quorum and arbiter

Hi,
Comments inline.

On Tue, Apr 18, 2017 at 1:11 AM, Mahdi Adnan 
<mahdi.ad...@outlook.com<mailto:mahdi.ad...@outlook.com>> wrote:

Hi,


We have a replica 2 volume and we have issue with setting proper quorum.

The volumes used as datastore for vmware/ovirt, the current settings for the 
quorum are:

cluster.quorum-type: auto
cluster.server-quorum-type: server
cluster.server-quorum-ratio: 51%


Losing the first node which hosting the first bricks will take the storage 
domain in ovirt offline but in the FUSE mount point works fine "read/write"

This is not possible. When the client quorum is set to auto and the replica 
count is 2, the first node should be up for read/write to happen from mount. 
May be you are missing something here.

Losing the second node or any other node that hosts only the second bricks of 
the replication will not affect ovirt storage domain i.e 2nd or 4th ndoes.

Since the server-quorum-ratio is set to 51%, this is also not possible.
Can you share the volume info here?

As i understand, losing the first brick in replica 2 volumes will render the 
volume to read only

Yes you are correct, loosing the first brick will make the volume read-only.

, but how FUSE mount works in read write ?

Also, can we add an arbiter node to the current replica 2 volume without losing 
data ? if yes, does the re-balance bug "Bug 1440635" affect this process ?
Yes you can add an arbiter brick without losing data and the bug 1440635 will 
not affect that, since only the metadata need to be replicated on the arbiter 
brick.
And what happen if we set "cluster.quorum-type: none" and the first node goes 
offline ?
If you set the quorum-type to auto in a replica 2 volume, you will be able to 
read/write even when only one brick is up.
For an arbiter volume, quorum-type is auto by default and it is the recommended 
setting.

HTH,
Karthik

Thank you.

--

Respectfully
Mahdi A. Mahdi


___
Gluster-users mailing list
Gluster-users@gluster.org<mailto:Gluster-users@gluster.org>
http://lists.gluster.org/mailman/listinfo/gluster-users

___
Gluster-users mailing list
Gluster-users@gluster.org
http://lists.gluster.org/mailman/listinfo/gluster-users

Re: [Gluster-users] Replica 2 Quorum and arbiter

[Karthik Subrahmanya]

Hi,
Comments inline.

On Tue, Apr 18, 2017 at 1:11 AM, Mahdi Adnan 
wrote:

> Hi,
>
>
> We have a replica 2 volume and we have issue with setting proper quorum.
>
> The volumes used as datastore for vmware/ovirt, the current settings for
> the quorum are:
>
>
> cluster.quorum-type: auto
> cluster.server-quorum-type: server
> cluster.server-quorum-ratio: 51%
>
>
> Losing the first node which hosting the first bricks will take the storage
> domain in ovirt offline but in the FUSE mount point works fine "read/write"
>
This is not possible. When the client quorum is set to auto and the replica
count is 2, the first node should be up for read/write to happen from
mount. May be you are missing something here.

> Losing the second node or any other node that hosts only the second bricks
> of the replication will not affect ovirt storage domain i.e 2nd or 4th
> ndoes.
>
Since the server-quorum-ratio is set to 51%, this is also not possible.
Can you share the volume info here?

> As i understand, losing the first brick in replica 2 volumes will render
> the volume to read only
>
Yes you are correct, loosing the first brick will make the volume
read-only.

> , but how FUSE mount works in read write ?
> Also, can we add an arbiter node to the current replica 2 volume without
> losing data ? if yes, does the re-balance bug "Bug 1440635" affect this
> process ?
>
Yes you can add an arbiter brick without losing data and the bug 1440635
will not affect that, since only the metadata need to be replicated on the
arbiter brick.

> And what happen if we set "cluster.quorum-type: none" and the first node
> goes offline ?
>
If you set the quorum-type to auto in a replica 2 volume, you will be able
to read/write even when only one brick is up.
For an arbiter volume, quorum-type is auto by default and it is the
recommended setting.

HTH,
Karthik

>
> Thank you.
>
> --
>
> Respectfully
> *Mahdi A. Mahdi*
>
>
> ___
> Gluster-users mailing list
> Gluster-users@gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users
>
___
Gluster-users mailing list
Gluster-users@gluster.org
http://lists.gluster.org/mailman/listinfo/gluster-users

[Gluster-users] Replica 2 Quorum and arbiter

[Mahdi Adnan]

Hi,


We have a replica 2 volume and we have issue with setting proper quorum.

The volumes used as datastore for vmware/ovirt, the current settings for the 
quorum are:

cluster.quorum-type: auto
cluster.server-quorum-type: server
cluster.server-quorum-ratio: 51%


Losing the first node which hosting the first bricks will take the storage 
domain in ovirt offline but in the FUSE mount point works fine "read/write"

Losing the second node or any other node that hosts only the second bricks of 
the replication will not affect ovirt storage domain i.e 2nd or 4th ndoes.

As i understand, losing the first brick in replica 2 volumes will render the 
volume to read only, but how FUSE mount works in read write ?

Also, can we add an arbiter node to the current replica 2 volume without losing 
data ? if yes, does the re-balance bug "Bug 1440635" affect this process ?
And what happen if we set "cluster.quorum-type: none" and the first node goes 
offline ?

Thank you.

--

Respectfully
Mahdi A. Mahdi

___
Gluster-users mailing list
Gluster-users@gluster.org
http://lists.gluster.org/mailman/listinfo/gluster-users